Fluid pressure producing device



J. R. HEIDLOFF FLUID PRESSURE PRODUCING DEVICE Filed Feb. 20, 1956 May24, 1938.

J H INVENTOR.

OSPH E/DL OFF www Patented May 24, 193s UNITED STATES PATENT OFFICE2,118,604. FLUID rarissima raoDUcnvG ,DEVICE Application February 20,1936, Serial No. 64,855

. '1 claims. (cl. eso-54.6)

This invention relates to fluid pressure systems, and vmore particularlyto fluid pressure producing devices for such systems.

KIn the production of fluid pressure producing devices including acylinder and a piston reciprocable" therein, the piston is generallyprovided with a plurality of spaced ports for by-passing fluid on thereturn stroke of the 'piston from the chamber back of the piston to'thatportion of the cylinder forward of the piston. The ports are generallycontrolled by a collapsible leak-proof cup seated on the head of thepiston. The cup is universally molded from flexible material, such asrubber, and is repeatedly subjected to high l5 fluid pressuresintroduced in the cylinder by movements of the piston on its compressionstroke. The high pressures deform the cup and compress the material fromwhich the cup isl made into the ports, resulting in injury to the cupand destroying the efficiency ofthe apparatus.

f In many fluid pressure producing devices of the-"type hereinabovedescribed the cylinder is provided with a port commonly known as acompensating port. This port is slightly in advance of. a collapsibleleak-proof cup seated on the head of the piston when the piston is inretracted position.y Because of the high pressures imposed on the v"cupduring the compression stroke of the piston, the wall of the cup isforced into the port.

This results, after repeated operations, in cutting a groove in the cupand destroying its efciency. it is the aim of the present invention toovercome these objections.

An object of the invention is to prolong the life of a packing member.

Another object of the invention is to provide a shield for a packingmember.

Another object of the invention is to provide a piston having aplurality of ports in its head controlled by a flexible cup, with aflexible shield arrangd between the piston and the cup to avoid injuryto the cup.

A further object of the invention is to provide a cylinder having aport, a piston reciprocable in the cylinder having a plurality of portsin its head controlled by a collapsible leak-proof cup, and a flexibleshield for protecting the cup against injury.

Other objects of the invention will appear from the followingdescription taken in connection with the drawing which forms a part ofthis speciflcation, and in which,-

Fig. 1 is a vertical sectional view of a fluid pressure producing deviceembodying the invention;

Fig. 2 is an enlarged fragmentary view in section illustrating a portionof the cylinder, the head of the piston, and the mechanism forcontrolling the ports in the head of the piston;

Fig. 3 is a plan view of the flexible disk; 5

Fig. 4 is an enlarged fragmentary view in section illustrating amodified form of the invention;

Fig. 5 is a plan view of the flexible disk employed'with themodification of the invention; 10 and Fig. 6 is a plan view of anothermodified form of the flexible disk.

Referring to the drawing for more specific details of the invention, IUrepresents a fluid reser- 15 voir of conventional type. A cylinder l2 atthe base of the reservoir has spaced ports I4 and I6 providingcommunications between the cylinder and the reservoir, and a removablehead I8 having a concentric opening constituting a discharge 20 port 20for the cylinder preferably controlled by a two-Way valve 22. Thedischarge port may be connected by a fluid pressure delivery pipe orconduit 24 to fluid pressure actuated motors for actuating the frictionelements of brakes, or other 25 fluid pressure actuated mechanism.

VA piston 26, reciprocable in the cylinder, may be retained againstdisplacement as shown at 28. This pistonhas a head 3U, a skirt 32, and asection reduced in diameter to provide in conjunction 30 with the wallof the cylinder lan annular chamber 34. A leak-proof washer 36 on theskirt of the piston provides against seepage of fluid from the chamber.The head of the piston is convex as shown at 38 and is provided with aplurality of 35 spaced ports 40 arranged in a circle, the center ofwhich is in the axis of the piston. The ports 40 provide communicationsbetween the annular chamber 34 and that portion of the cylinder I2`forward of the head of the piston. 40

A exible disk 42 is seated von the head of the piston. This disk ispreferably stamped from relatively thin sheet metal stock having suchcharacteristics that it may be easily flexed to conform to the profileof the head of the piston 45 without developing fatigue, crystalization,or otherwise injuriously affecting the disk. 1 The diameter of this diskis slightly less than the diameter of the piston head, yet sufficientfor the disk to completely cover the spaced ports 40 when it 50 isflexed to conform to the head of the piston. l

A pin 4I is mounted concentrically on the disk 42, and a collapsibleleak-proof cup 4B seated on the disk has a concentric opening receivingthe pin and a marginal flange or lip engaging the 56 wall of thecylinder. The cup centers the disk in the cylinder so as to eliminatethe possibility of the perimeter of the disk scoring, chafing orotherwise injuring the wall of the cylinder. 'I'he cup is also free torotate relative to the disk and with the disk so that injury to the cupdue to its movement over the port I6 while under pressure is reduced toa minimum. A spring seat 46 positioned on the cup has a concentricopening receiving the pin so as to center the seat in the cup, and aspring 60 interposed between the seat 46 and the two-way valve 24retains the assembly of the disk and cup on the piston head and thevalve 22 on its seat. This spring also serves to return the piston toits retracted position. A thrust pin 62. seated in a recess in the backof the piston and suitably connected to any desirable type of actuator,may be employed for moving the piston on its compression stroke.

A modification of the invention is illustrated in Figs. 4 and 5. In thismodification the head of a piston corresponding to the piston 26 has aconcentric recess 64. A flexible disk 56, having the samecharacteristics as the disk 42, is concentrically swedged to provide aprotrusion 58 on its back and a recess 6I) on its face. The protrusion66 is received by the recess 64 in the head of the piston so as tocenter the disk 56, and this protrusion provides a trunnion on which thedisk may be freely rotated. A collapsible leak-proof cup 62, similar tothe cup 46, is seated on the disk 56. This cup has a concentricprojection 64 fitted in the recess 60 so as to center the cup on thedisk and to provide for relative rotation between the cup and the disk,and a spring seat 66 in the cup receives one end of a spring 66corresponding to the spring 50.

Another modification of the disk is illustrxted in Fig. 6. In thismodification a disk 10, of the same general characteristics as the disks42 and 66, is cut away to provide a hub "I2, preferably corresponding tothe central portion of the disk 66, and a plurality of spokes 'I4supporting a rim 16, the rim being of sufllcient width to completelycover the ports 40 in the head of the piston when the disk is exed toconform to the profile of the head of the piston. The advantage of thisparticular type of disk over those hereinabove described is theincreased flexibility of the disk due to its skeleton-likecharacteristics. However, it has its disadvantage in that relativerotation between the disk and the leak-proof cup seated thereon ispractically impossible due to the tendency of the disk to becomeembedded in the back of the cup after the cup has been repeatedlysubjected to high fluid pressures. Hence, when this type of disk isemployed, the disk and the cup rotate together.

In operation, upon advancing the piston 26, pressure is created in thecylinder I2 forward of the piston. Ihis pressure is 4received on the cup46 supported on the disk 42, resulting in flexing the disk 42 to conformto the convex head of the piston and effectively closing the ports 40.Further movement of the piston displaces the fluid from the cylinder I2past the two-way valve 22, and through the fluid pressure delivery pipeor conduit 24 to the fluid pressure actuated mechanism.

Upon release of the applied force, the piston 26 is returned to itsretracted position under the influence of the spring 50. As the pistonreturns to its retracted position a partial vacuum is created in thecylinder forward of the piston and pressure on the cup 48 and the disk42 is released, resulting in the disk assuming its static condition andthereby uncovering the ports 40 so that fluid may be drawn from thereservoir I0 through the port I4, the annular chamber 34 and the ports40 in the head of the piston, past the leak-proof cup 46 into thatportion of the cylinder I2 forward of the piston to completely fill thecylinder for subsequent operation.

Because of the provision for relative rotation between the cup and thehead of the piston, wear on the cup incidental to its movement over theport I6 may be more evenly distributed, and hence the life of the cupmay be prolonged. Rotation of the cup relative to the piston may becaused by the action of the spring 50, by the flow of fluid around theperiphery of the cup, or by variations in the cylinder wall.

Although this invention has been described in connection with certainspecific embodiments, the principles involved are susceptible ofnumerous other applications that will readily occur to persons skilledin the art. The invention is, therefore, to be limited only as indicatedby the scope of the appended claims.

Having thus described the various features of the invention, what Iclaim as new and desire to secure by Letters Patent iss- 1. In a fluidpressure producing device, a cylinder, a piston reciprocablein thecylinder having a port therethrough, a flexible disk on the pistonrotatable relative thereto, said disk having a portion normally spacedfrom said port, but flexing under pressure created in the cylinder tocontact said port, and a flexible cup centered on the disk, said cupcontrolling fluid flow through said port.

2. In a fluid pressure producing device, a cylinder, a pistonreciprocable in the cylinder having spaced ports therethrough, aflexible disk on the piston rotatable relative to the piston, and aflexible cup on the disk rotatable relative to the disk, said cupcontrolling fluid flow through said ports.

3. In a fluid pressure producing device, a cylinder, a pistonreciprocable in the cylinder having spaced ports therethrough, aflexible disk on the piston rotatable relative thereto, a flexible cupon the disk, said disk having portions normally spaced from said portsbut flexing under pressure created in the cylinder to contact saidports, and means for centering the cup on the disk and permittingrotation of the cup relative to the pist0n.

4. In a fluid pressure producing device, a cylinder, a pistonreciprocable therein having a convex head provided with a plurality ofspaced ports therethrough, a flexible disk on the head overlying theports and rotatable relative to the piston, a flexible cup seated on thedisk, and means for centering the cup on the disk and permittingrotation of the cup relative to the disk.

5. In a fluid pressure producing device, a cylinder, a pistonreciprocable therein having a convex head provided with spaced aperturestherethrough and a concentric recess, a flexible disk on the head havinga part received by the recess for centering and supporting the disk forrotation, a flexible cup on the disk, and means for centering andsupporting the cup for rotation.

6. In a fluid pressure producing device, a cylinder, a pistonreciprocable therein having a convex head provided with spaced aperturestherethrough and a concentric recess, a flexible disk on the head of thelpiston having a concentric deformed portion cooperating with the recessthrough and a concentric recess, a exibie disk on the head of the pistonhaving an embossed center and portions out away to enhance theflexibility of the disk, the embossed center cooperating with the recessfor centering and supporting the disk for rotation, and a flexible cupseated on the disk having a concentric projection on its back receivedby the embossed center of the disk.

JOSEPH R. HEIDIQFF'.

